In Sex, Molecular Forces, and Coffee Stained Textbooks
by bellenowing
Summary: A ScienceBros Professors!AU. Bruce Banner was recruited by S.H.I.E.L.D. to co-lead an elite group of students on a new project on molecular forces. Little did he know, his teaching partner was rich, famous, and an absolute asshole. As the project went on, the tension between them shifted and something sparked into something else, what bonded them grew from science to everything.
1. Prologue

**A/N: Hey guys. This is a collaboration account, and this is our first piece of work together. This will be multi-chaptered, and un-betaed by anyone except for us two (and we're very, very careless). Anyway, here we go.**

**-Belle**

* * *

><p>The solution bubbled from the flask through the tube. Bruce watched as the level in the syringe steadily increased, and stepped out of the lab, satisfied.<p>

"Mr. Banner," A strongly accented female voice called. "There's someone on the phone for you."

"Where is it from?" Bruce covered the receiver and took the phone from Rana's hands.

"America, Mr. Banner. New York."

Bruce looked up alarmingly. "I thought I had made it clear that no phone calls-"

"This isn't regarding your experiment, Mr. Banner. This is from a school."

"Did they say what they want from me?"

"I believe nothing to do you with your current experiment, Mr. Banner. They didn't seem concerned about it. Would you like to take the call and find out, Mr. Banner?"

Bruce hesitated, his palms still over the receiver. Finally, he took it off and raised the speaker to his phone.

"This is Bruce Banner."

There was a shuffle on the other end. "Hello, Dr. Banner? This is Natasha Romanoff, the secretary of Directory Fury of S.H.I.E.L.D."

"Right...S.H.I.E.L.D?" Bruce repeated, dragging a chair out from underneath the table. The name sounded familiar, but he could not get the exact image. The name was repeated in his head until he remembered. "S.H.I.E.L.D, as in the...university? S.H.I.E.L.D?" He questioned tentatively, not that he was very sure about the name himself.

"Yes. That is it. We have been in the search for you for a while now, Dr Banner."

"Right." The sense of uneasiness clung to him. 'In the search' was a phrase he dreaded.

"Have you ever taught? Or tried teaching?"

"I'm sorry?"

"Teaching. You are one of the most well-known gamma-physicist of today. Have you ever considered teaching?"

"No. I'm not-I'm not so sure I can do that." Bruce scrunched his eyebrows, trying to predict where the conversation is going. "You want me to-you want me to teach? At your school?"

"Yes, just that. S.H.I.E.L.D has recently gathered a new team of young scientists, elite students of the institute. We are in need of an experienced teacher to lead them. A chemical physics project. A lot to do with quantum physics, gamma rays, molecular forces...I presume you are familiar with it?"

"Yes, but-"

"Dr. Banner, we can discuss the details of the job after you arrive."

"Arrive?"

"Given that our school is located in New York City, it would be ideal if you could fly back to the United States. We will arrange the transportation."

"No, look, I'm sorry, but I'm not looking for a job. I have many studies going on here."

He could hear a muffled conversation going on in the background. It was Natasha, and a masculine voice. It did not go for long until the talk was replaced by the noise of typing. Bruce frowned in confusion and held the phone closer as if it would have give him more clue on what was going on.

Before he had time to think anything through, the female voice resumed.

"Dr. Banner, the Head of our school wishes to converse with you. I will switch you onto his line."

"What-?" Bruce barely stuttered out when he heard a click on the other end. There was a beep, and the line was picked up again.

"Hello, Dr. Banner, I understand you have chosen not to participate in this study?"

"Right, and who is this?"

"Director Nick Fury of S.H.I.E.L.D. Is there anything I need to explain?"

"No, look, the connection is bad here, but I don't think you've heard correctly-"

"Vacuums, Dr. Banner, I believe you are familiar with them."

"Yes, vacuums. Several has been built in Europe. Only the highest of authorities can access them. A research center in Oregon has been developing one for a few years now already."

"Well. I'm hoping you would like to learn that we have recently fully developed and built an underground vacuum. It is close to being complete. I am hoping you will be willing to co-lead a group of students through various new studies in the vacuum involving molecular forces and such."

"What?" Bruce gripped the phone a little bit tighter. "A...fully developed and built vacuum? In...New York? Underground?"

"Yes. I presume this is a lot to process. You are invited to instruct this group of students. Would you like to reconsider your answer?"

"But there was absolutely no talk about this, this vacuum?" Bruce scanned through the science forum sector of his mind. He HAS been away for a while now. What has he missed?

"It is something we'd rather keep private to just the institute for the time being. We will release more to the public once the experiments are initiated."

"And we-and I will get full access? To this...this vacuum?"

"Yes. Would you like to kindly inform us of you nearest available time so we can arrange the transportation for you to get here?" The voice on the other end was distant and impatient, but Bruce was too busy processing the information to notice.

"Nearest available-right. Uh..." Bruce was disoriented, feeling around for his glasses. "I'm not really-I'm not really that busy. I mean, my studies here can wait."

"Would it be convenient for our issued car to meet you outside your lab at eight am tomorrow?"

"My-my lab?"

"Yes. Your cellular data shows where your exact current location is. Would eight am be good?"

He was astonished at first by how omniscient they sounded, then he came to realised that they could probably do a lot more than just track his location down. The wonder of how much the S.H.I.E.L.D can do would probably be a never answered question in his head.

"Um, I see. I think that will work," Bruce was still overwhelmed, moving in a haze and reaching for a pen. He wasn't sure why, but he jotted the time on his calendar. "Right, um, I'll be there."

"We shall meet soon, Dr Banner." The other end clicked as his voice finished. Bruce held the phone by his ear for a few more seconds, still in shock, then promptly put it down upon realizing how dumb be must have looked.

"Mr Banner, is everything okay?" Rana approached him, reaching out for the phone.

Bruce rubbed his eyes, still feeling numb. He slipped off his glasses.

"Right...Yeah, sorry, yes, everything is alright. I'm-" There was a small pause, a hesitation, before he said it out loud. "I'm going back to the States tomorrow."


	2. Chapter One

Bruce felt his ears pop as the plane descended from the stratosphere. The windows trembled as the air pressure compressed the plane, and Bruce felt his stomach churning. A book was laying on the open table, the pages open to where he previously stopped, pages facing the tabletop and the spine was facing upwards. He set his reading glasses down, rubbing his eyes, slightly nauseated.

Bruce stared out the window and watched the city skyline as the plane body got lower and lower, until eventually the back wheels landed first and the plane thumped slightly, then started the taxi along the runway.

The plane slid along the back of a small airport, before finally stopping in the middle of an open field. Bruce gathered his belongings, sliding them all in his messanger bag, and the door sucked open.

A sense of dizziness overwhelmed him as he stood up, and he gripped the luggage racks above him with his right hand to steady himself. The flight was just a little under sixteen hours long, and _thank god the school issued a private jet that flew directly to, _because there was no way he was going to endure the torture of transferring flights.

A black car was parked beside the plane, and the door to the driver's side opened as Bruce made his way down the stairs.

A figure stepped out of the car, clicked a button on his earpiece, and put on a warm smile. "Welcome, Dr Banner."

"Hi." Bruce made his way toward the car as the man opened the passenger seat's door for him. "Is this-we're going to SHIELD?"

"Yes." The smile reached the man's eyes, showing small crinkles. "I'm Phil Coulson. Directory Fury is waiting for you. We will be going to your living quarters first. Director Fury has arranged for you to rest, adjust to jet lag for a few days. Re-accommodate yourself to the country. You have been out of the country for a while now, Dr Banner, if I remember correctly?"

"Six years." Bruce gazed out his right, out the window. He was not used to the difference in height, and he took note of how different the airport looked from the plane and from the Mercedes.

"Wow." Phil squinted through the late-afternoon sunlight. "That must've given you enough time to get your research going."

Bruce nodded, only to realize that there was no way Phil would be able to see that, given how both of his eyes were glued to the road ahead of them. Bruce coughed, and muttered a low "uh huh…"

"So. Director Fury told you anything about your project yet?" Phil asked absently, his hands on the steering wheel.

"No. Not much. Uh...vacuums?"

"Anything about your partner?"

"My partner?" There was a sinking feeling in Bruce's stomach. There was a reason he spent six years, alone, with almost no disturbances, in a small town in rural India.

"Ever heard the name Tony Stark?" Phil's eyebrows were slightly raised, his lips tucked into a tight smirk.

"No…?"

"Well." Phil coughed, biting his lower lip, unable to contain an ominous smirk. "You will meet him soon enough."

Bruce felt an uneasy sense of dread and nervousness in his chest, and he sat up a bit straighter and stared out the window for the remainder of the ride.

His 'living accommodations' turns out to be a spacious apartment five miles west of the university campus. It wasn't particularly large, but it was lots of space for New York. S.H.I.E.L.D. wasn't in the city, but by the south tip of Westchester, just under thirty miles north of Manhattan.

He'd dumped his small case of luggage by the door and took half an hour to get himself cleaned up before collapsing onto the bed. It was three in the morning back in India, and he'd only gotten about an hour of shoddy sleep on the plane.

The bed was too soft, but he had to deal with it for the night. His bare feet couldn't get used to the carpet on the floor of his bedroom, but he told himself he would figure out away the next day.

He was in bed by six o'clock at night, but didn't manage to fall asleep until after the lights dimmed in all the other buildings around him. It was just the light, he told himself, and the mattress and the carpet and the running hot water and the lack of humidity in the air. _You'll be fine_, he thought to himself.

_You'll be fine._

The next day was well spent.

There was Internet in the apartment, custody of S.H.I.E.L.D., and the connection was a hundred and one percent better than the one back in India, provided by the rusty satellite dish Bruce had set up himself. He needed space for his lab back in India, and given the population density in urban Indian cities, he had to travel hundreds of miles west of Calcutta before he found enough land for his equipment.

He'd checked his email, and found one from Natasha Romanoff, with a domain that started with a question of how he was adapting into the country and proceeded into listing out the schedules. S.H.I.E.L.D. is not messing around, he realized as he saw that his first meeting at the school would be the next day.

He needed a nice suit. All he had as a change of clothing was his purple shirt, a shaggy blazer with a hole in the pocket and the same worn-out belt. He'd visited the mall, spent hours just gaping and the variety of things and then reminding himself to close his mouth while staring. He was stressed out by the choices, prices and the over-eagerness of the salesmen at each store. He ended up purchasing two more shirts and an oversized blazer before hastily leaving the mall.

And then he bought a microwave, a living essential he could not believe S.H.I.E.L.D. hadn't already placed it in his kitchen for him. He had a freaking _spatula_ but no microwave. He shopped for frozen food, trying to remember the brands he favored when he was younger. He remembered the mattress when he stood in line at the check-out, but it was late afternoon and he could not be bothered to go through shops and shops and displays and displays of mattresses to _just pick out one that he could _fall asleep _in_.

A wave of exhaust washed through him as he stood in front of his apartment door, rummaging for his keys. He moved the stuffed plastic bags in, suddenly longing for _science_. He felt bad for leaving his old experiment just like that, but it wasn't like it was going anywhere. He hadn't anticipated much. But here-with the vacuums, it was a whole new aspect of science. He had never had the chance to even _visit_ a vacuum, much less conduct a whole series of studies in one.

He was nervous about teaching. He has never taught before. Natasha had informed him that it was just like making a speech, but he hated making speeches, he hated speaking about his passion in front of an auditorium full of strangers in grim suits with half of them actually listening and half of them only present for a university course. He didn't like all the attention on him. He hoped instructing was easier than making a speech.

He felt the thin blanket over him and the soft springs beneath him as he tried to fall asleep. Something was unsettling, and he relocated to his carpeted floor just before the green flashing numbers on his alarm clock turned to midnight.

Sleep welcomed him.


	3. Chapter Two

Bruce woke up exactly six minutes before his alarm.

He went through his usual morning routine, the minty toothpaste stinging his tongue. There was a quick sweep in his fridge and cupboard to make sure there was no edible breakfast food, then he pulled a jacket off the hanger, reached for his messanger bag, then reached for his keys before stepping out of the apartment.

Bruce left his house an hour early to prevent arriving late. Perhaps he could get a coffee on the way? He thought to himself. The autumn morning was cold, and he shivered a bit to the chilling wind. Apparently his jacket wasn't enough to keep him warm. He paced up to find a cafe not far away from him acrossed the street.

That's it.

There was a clear ring when he opened the door. He looked up to find a set of bell on rim of it. His arrival didn't bring much attention since people were all at the counter, hoping to start their morning with a warm cup of coffee. Bruce scanned around before proceeding. It was not too crowded given the time. A few people sat beside the counter on the armchairs, a few were still waiting for their order.

Bruce liked the relaxing atmosphere, and decided this was where he would stay before heading out. walking up to the queue, he looked down to his watch to find a good ten to twenty minutes he could use to get something to drink. This, and then S.H.I.E.L.D., he thought to himself.

This was when he bumped into something. Bruce looked up in surprised, there was no obstacle a moment ago as he remembered. In front of him stood a man. He was not young, but not too old. Taller than Bruce, that he was sure of. The man had a set of grey suit on, it was not too tidy. Wrinkles around the collar, the left open second button of his shirt, and the sleeve that was probably attempted to be rolled up but slided down again. From the look of the suits you could tell it was either very expensive, or it was made to look so expensive in contrast of that man's even sloppier face. Bruce hesitated to made a decision amongst the two. The man obviously did not shave that morning. Stubbles, and some thicker part of facial hair that- probably were the actual bread. A pair of aviator glasses covering the man's eyes. The others head was tilted forward, looking down on his mobile device.

He did not look up immediately, instead acted a moment later. Head did not move, but Bruce knew when he was seen. The other man paused, eyeing him up and down, and drew a light smirk. That was most definitely what made Bruce dislike him first.

Silence.

"So are you going to apologise or what?"

Bruce frowned.

"Excuse me?"

"Excuse you mister for bumping into me."

"Uh, no? I am pretty sure you are the one focusing on your phon-"

"Yeah sure I accept your apology I don't have time to argue. Bye-bye," said the man, pushing Bruce to the side and walking away by the time he finished the sentence.

Bruce was annoyed. His expressions froze in astonishment. Not that he did not know this kind of people existed, but shocked by how _lucky_ he was to meet one of them. Finger massaging his forehead, he decided not to waste any more time looking defeated. That's life Bruce, jerks are everywhere. He thought to himself helplessly.

The argument did not seemed to catch more attention; he walked forward and actually joined the queue this time.

He was not late when he arrived. Phil greeted him with the familiar polite manner and led him inside the academy. He toured the first and second floor, surprised by the amount of advanced technology products in the building. It must have been a fortune to study here.

Walking through the corridor, he started to admire the atmosphere. Maybe teaching wouldn't be so difficult in this environment. Maybe it would even help him with his own research. A spark of hope bloomed in him, and suddenly made him a lot more confident on moving back to the USA.

"Alright, this is where you two will be teaching," Phil stopped in front of the third classroom down the third floor corridor.

"Oh yes. Tony Stark," he remembered the name. Future partner, it had a nice ring to it at the beginning, not sure if it still did. Not that Bruce was unwelcoming, but he wasn't sure who that 'Tony Stark' might be. Hopefully someone as passionate as he was on the subject of science? He shouldn't be expecting so much.

Phil knocked and stood at the threshold, introduced:

"Director Fury, Mr Stark-Dr Banner is here."

"It's going to be fine," he thought to himself, "it's always good to think positive even if it's the worst situation right?" and with that, he followed in with Phil.

"-and , this is Mr Tony Stark," Bruce's sight followed the direction Phil gestured towards, and-

The hair, the aviator glasses, the smirk, the untidy suit, _the man._

Eyes widened.

Bruce changed his mind about being positive immediately.


	4. Chapter Four

Chapter Three

"Nice...to meet you, Mr...Stark." Bruce cringed inwardly as the name sounded out. _Holy hell._

"Tony." The man flashed Bruce a quick smile as he took off his sunglasses, giving what Bruce caught as a small wink.

"Bruce." He wasn't sure whether or not the man would even _shake_ his hand, but held it out hesitantly anyway.

"Well, I'm testing out the new equipment, so I'll see you in a while." Tony took his hand, _thank God_, and shook it once, firmly, before letting go.

"Hold on, Stark." Director Fury called out before Tony could turn around and leave the room. "You and Dr. Banner would be teaching together this year. You might want to go over some notes with him." The word _notes_ was pronounced with extra dryness.

"Right. Uhh...Notes. We had to make notes? I figured we'd just teach from the syllabus."

"Stark, this is an elite team of students being led for studies. This is the first large vacuum chamber in continental United States, I don't think we have a syllabus for that yet." Fury sighed. "You know what? Why don't you take Dr. Banner to the vacuum. Show him around. Familiarize with the surroundings, whatever it is you do."

Tony let out a grunt, shoving his left hand in his pocket as he reached out to open the door. He walked out without bothering to hold the door.

"So, India." Tony lead the way to the chamber. "Why India?"

"Um." Bruce was caught off-guard. "In-India? It was...it was quiet, I guess. I didn't like the, you know, _scandal_ back here. I figured I could use some alone time. Allows me to focus on experiments and such, you know?"

"Six years of alone time? Geez, you really didn't get enough time-outs as a kid, huh?" Tony remarked, typing a six-pinned code into the keypad at the entrance of the vacuum chamber.

Bruce didn't know which stance to take, so he figured defensive was the safest. "So you've read into my background."

"Your file was on Fury's desk." Tony waved it off. "Skimmed through it."

Bruce kept his mouth shut. There _were_ things he could say, but he didn't want the partnership to start on the wrong foot. Actually, it already did, when they bumped into each other in the coffee shop earlier.

"So, um, the password thing-" Bruce gestured to the keypad lock on the metal doors, and Tony interrupted him.

"One-one-six-five-oh-two. I'll probably be here, though. I doubt you'll really need it." Tony made a point of getting his words out fast. "Bet they don't get vacuums in India."

"Nope. I barely had a satellite. Or neighbors, in fact." Bruce wasn't sure what point Tony was trying to get across.

"Well, we've got a large one. You know, the NASA-styled kind. Vacuum chambers, I mean. Thermal vacuum chamber. Back there, we got vacuum labs. Smaller vacuums. For the smaller stuff. You know, molecules. Ions. That kind." Tony rambled on, but briefly paused in the middle, turning behind to look at Bruce. "You learned this shit in school, right?"

Bruce looked at the other man incredulously. "I'm...pretty sure?" Because _what the fuck,_ _that's basic chemistry?_

"Well yeah, just checking." Tony hummed as he turned back around and made his way down the metal doorway. There was a last door, and Tony pressed the handle down and pushed the door open, revealing the large chamber in front of them.

"My last few 'teaching partners' didn't exactly know what they were doing. I'm hoping you're at least a bit better than that." Tony said, but Bruce caught none of it. He marvelled at the wonder in front of him, the concrete cylinder block that stood majestically before them.

"Yep, I know. Pretty cool, huh?" Tony walked down the balcony-pathway that went around the vacuum, and Bruce couldn't help but stare in awe as his feet followed.

"That's...that's…" He struggled to find a suitable word for it. "This is all underground?"

"Yep. All ninety feet of it." Tony offered, reaching another door. "And here is the Chemistry department."

"What do you _do_ with that kind of sized-chamber?" Bruce's mind was still on the vacuum.

"God knows. S.H.I.E.L.D. doesn't know what to do with all their fundings." Tony types in another set of passcodes. "Close your mouth, will you?"

Bruce hadn't realized he was staring with his mouth open, but he shut his jaws together promptly.

"NASA uses theirs for spaceship testing, but I guarantee you we don't have spaceships here. I don't know why it's so big, but they suggested we can do molecular testing in these too. Space to move around, stuff like that. More Physics oriented. You know, seeing particle movements with no resistance force."

"That's ridiculous. We already _know_ what would happen without resistance force."

"You don't _know_. All you _know_ is a theory, Bob."

"Bruce."

"Bruce." Tony corrected himself quickly. "All you know is a theory, theorized by thousands of scientists who study other scientists' works and more or less agree with each other. The chamber is built to put that theory into practice. And anyway, there are lots you can do with moving particles. But _anyway_, I'm hoping our focus could be on Chemistry. Here's the lab." The metal door buzzed open and Bruce followed Tony in in a daze.

On the other side of the door was the biggest vacuum lab Bruce has ever seen, ever been lucky enough to witness.

"This is...amazing," said Bruce, still marvelling.

"Not the most vivid adjective ever, but on point, it _is_ amazing." Something that resembled a smirk formed by the tip of Tony's lip. "This is where all the smaller stuff happens. Electromagnetism research...Obviously this is still a partial vacuum, but it's as close to a perfect vacuum as we can get. These vacuums are improving day by day, though. We're getting closer and closer to a perfect vacuum, by fractions of fractions everyday. It's not a whole lot, but considering how close we are, it's plenty. I've worked all summer with the engineering team. I'm the best they've got. It's kind of like making your own apparatus. I guess. Sort of. You do any chemical engineering?"

It didn't register in Bruce's mind that Tony was asking a question until an awkward moment later. "Uh...no. I'm more of the...physicist kind."

"Ahh. Physics. I guess we can work with Physics. Quantum theories...eh, I'll sacrifice my molecular movement time for that." Tony waved the subject off with his hand, and Bruce felt his eyelid twitch. "Anyway," Tony continued, "that's basically it. I'm going to go work with the engineering team now for a bit. You can hang around here, or whatever."

Bruce opened his mouth, questions already tumbling from the tip of his tongue, but Tony flashed him a smirk, and threw his right palm up into a wave.

"Bye-bye." The stubbled face turned away, and the smaller man turned a corner and disappeared.

Bruce let out a sigh as he started back toward the vacuum labs. He was going to have the entire quantum theory attempted before lunchtime.


End file.
